Removable floor or wall covering



PatentedJan. 11,1949

2,458,750 REMOVABLE FLOOR OR- WALL COVERING Samuel G. Trepp, Bird & Son,inc.,

Dedham, Mass, assignor to East Walpole, Mass, a corporation ofMassachusetts No Drawing. Application April 2-, 1946,

Serial No. 659,159

2 Claims. (Cl. 154-49 1 This invention relates to a removable floor orwall covering of the hard-surfaced flexible type. The inventionprincipally concerns a floori covering having a felt base saturated witha suitable hydrocarbon semi-solid bituminous, or equivalent, fillingmaterial and having an ornamental wearing layer of paint, ornamentedpaper,

linoleum, or other plastic mixture applied to the base to improve itsornamental appearance and wear resistance.

To wear satisfactorily, floor coverings of the flexible type should befirmly anchored to the sub-surface since looseness is likely to resultin scufiingrup, bulging and cracking of the covering. This isaccomplished by attaching the covering to the sub-surface with a layerof cement, such as linoleum paste, which functions not only as a bondingmedium but also to smooth over and fill irregularities in thesub-surface. The practics of cementing down the covering, while in mostcases a practical necessity for proper wear, has caused" much diiiicultyin removal of worn coverings for replacement. The problem has beenparticularly extreme v base type of coverings since the cement bond ofsuch a base to a sub-surface is normally stronger than the comparativelyweak tear resistance of such covering material.

To alleviate this removal-difilculty, it is common practice in the caseof floor coverings to first cement, by means of. a water solublecomposition, a layer of lining felt cement the floor covering to thelining felt. When the floor covering is removed from such aninstallation, the initial rupture occurs in the lining felt. Theresidual lining felt and-cement remaining on the floor can be thenremoved with water. This method is undesirable because of first, theadded cost of the lining felt, and secend, the increased tendency of thefloor covering to dent.

Hoposals for eliminating the lining felthave included interpositionbetween the saturated felt of the floor covering and the cement of alayerusually in the form of a back coating on the feltof a materialwhich is more easily ruptured than the saturated felt, or else has sucha weak bond to the saturated felt, relative to its own internal cohesivestrength and that of the saturated felt, that, during removal, the twolayers will preferentially cleave and separate along the plane ofcontact or interface between the layer and the felt base.

None of the materials suggested in these proposals had, however, beensatisfactory. Thus,

in the case of the felt to the floor, and then "of this type has 2 anearly suggestion was an interposed layer of a cohesively weak Montanwax. A back coat of such material, however, required high temperatureapplication to the asphalt saturated felt,

and at best, was brittle and had poor aging properties. Little, if any,better results have been secured by utilizing materials such as gums andacaroid resins. Layers of all these materials are so brittle that underconstant impact of trafiic they shatter and powder, with resultantprogressive impairment of the bond of the floor covering to thesub-surface to such an extent that the bond is often completelydestroyed long before the expiration of the normal wearing life of thefloor covering. When this happens, as it usually does, the advantages ofcementing are secured for initial periods only, and the likelihood ofscufilng, bulging and cracking, after the weak strength layer at heavytrafiic locations has crumbled, is greater than if no cement had beenused.

Further, many of these materials are waterlnsoluble and thus requireexpensive solvent spreading (for instance, alcohol and the. like) andtheir residue adherent to the laying cement after stripping of acovering is not readily removable by water-washing.

In an attempt to improve on these foregoing materials, Bradley PatentNo. 2,341,078 describes a layer formed from a multiple emulsion of oil,I

casein, wax, fatty acid, and pigments. A layer fairly strong-cohesion,and removabillty of the floor covering is afforded by reason of therelatively weak adhesion of the layer to the saturated felt base. Asstated in that patent, the mechanism of cleavage is not fully understoodand, in practice, it has been found that pull-oil characteristics havevaried widely between manufacturing runs, apparently throughuncontrollable preferential wetting of the saturated felt, with theresult that, unless extremely careful control's 'are set up andmaintained, the products do not remove satisfactorily from subsurfacesafter cementing. When, to this manufacturing variation is cumulativelyadded the complication in the preparation of the=multiple emulsion mixof the Bradley patent, with its hightemperature expensive wax melt, theproduct becomes commercially diflicult.

Despite the above proposals, dry back felt and duplex felt floorcoverings are still offered on the market and widely used, though a,truly satisfactory removable saturated felt would completely displacethese compromise products which have their individual drawbacks inragged cutting, too quick cement 3 i drying for cutting seams and forinsert work, and tendency to dent. This invention provides such a trulysatisfactory removable saturated felt product.

In accordance with this invention it has been found that a saturatedfelt floor or wall covering may be provided with a back-coatingthebonding strength of which to the saturated felt or the internal cohesivestrength of which, whichever is less, is fully sufilcient to insure thatthe floor coveringzmaterial will not tear loose under norinal traflic.conditions, but is less than themternal strength of the saturated feltso as to permit'ready remova-bilit of the floor coveringcompounded fromnatural or synthetic rubber or latex, of reclaimed rubber, vulcanizingingredi- ,e-nts, a water-soluble binder pigments and/or 'fillers. Suchcoatings, in

' Parts by weight Dispersed reclaimed red inner tube stock (55% solids)23.8 Pigment (red slate flour) 100 Vulcanizing ingredientszinc oxide(Kadox 15) .6 Sulphur (50% dispersion) 8 Accelerator (butyl zimate 40%)Casein (as 10% solu.) 35 to 55 Wateras needed A stable casein solutionwhich has been found suitable is made as follows:

Six hundred fifty-five (655) grams of water are heated to 165. Withagitation, 8 grams sodium fluoride, 1.2 grams ammonium oxalate and 10.3grams borax are added. Then 76 grams casein are slowly added and the mixagitated at 165 for 30 minutes.

The above dispersion may be made in the following manner:

The casein solution is added to a vessel fitted with good agitation andthe sulphur, zinc oxide and red slate are added in that order. the pasteis uniform, the rubber dispersion is added, and then the accelerator.Water is added to suit, depending on the method of application to beused. For roller coating application it may be necessary to add ananti-foaming agent, such as pine oil to prevent undue fiufiing.

The dispersion is stable for only about 24 to 48 hours, but will remainstable for much longer periods if the accelerator be withheld. Asaturated felt which may or may not have been first thinly coated withan ordinary high strength bond paint solution or emulsion, such as anoilresin-pigment mixture, to provide a smoother surface, is coated, asthe above dispersion,

with a doctor blade, with and is then baked at 150 to 170 F. for atleast one hour to vulcanize the coating. This is followed by usual floorcovering operations involving lamination of a tread surface to thesaturated felt and the subsequent curing of the entire article for, inthe extreme case of Whenlinoleums, from 5 to 20 days at elevatedtemperature, depending upon the particular nature of the tread surface.Shorter cures are suflicient in the case-of printed felt bases. In somecases decorative or other coatings may be applied over the rubbercoating in any stage of the operation subsequent to the application ofthe dispersed rubber coating.

addition to having Where the rubber coating is applied directly tothe'saturated feit, satisfactory results have been secured with thespreading equipment set to spread from 24 to 35 lbs. (dry weight) of thecoating material per 100 sq. yds. A coating of this thickness issufficient to withstand ordinary linoleum baking cures without'becomingtacky, staining, or being otherwise adversely affected. The coatingafter curing will also neither stick nor stain when tested as follows.The sample to be tested is placed rubber coat down; against the face ofa nitrocellulose lacquered linoleum and is weighted with a dead weightof 100 lbs. per sq. inch and left under conditions of 100 F. and betterthan 75% humidity for at least one hour. The sample should lift freewithout any sticking to the underlying surface and should show no signsof stain.

Where a smoothing coat of paint underlies the rubber coating, or wherethe cure is less severe, the amount of rubber coating may be cut downsomewhat without loss of stick and stain freedom. I

The saturated felt-to-hardened linoleum paste bonding strength of thevulcanized rubber-pigment coating made as described above, 55 partscasein solution being used, was uniformly between 8 and 15 lbs. whentested on a pull'on a Scott tensile strength machine in 5" widths afterbeing subjected to the -10 day linoleum bake. This range is below theinternal cohesive strength of saturated felt which runs upwardly from aminimum of about 15 lbs., but is usually above 25 lbs. in 5" widthstrips. However, the particular bonding strength may be varied, byvarying the pigment to casein ratio, within the range of 2 to 25 lbs.per 5" width strip. This bonding strength, however, in practice must bemade less than that of the particular felt employed so that floorcovering when being stripped will not break in the substance of thefelt. In general, increase of casein will increase the bonding strength,and vice versa.

The break in the aboveexample occurred in the backing near-the saturatedfelt-backing interface. It is found that the strength of the bond may bevaried somewhat by a variation in formulation, but that it differs aswell with a change in coating method and equipment. The data above isrepresentative of backing applied in the laboratory by means of a Birdfilm applicator. Generally, roller coating application has given aweaker bond.

It has also been found that if a thin coat of an emulsion paint isapplied on the saturated 'felt before my backing, the bond between thispaint and my backing is usually stronger than between. saturated feltand my backing. I have further found that as the amount of emulsionbacking is increased up to 10 lbs. per sq. yds., the bond is increased.

It is obvious that if the internal strength of my backing is greaterthan its bond to saturated felt or a protein paint, the cleavage will beat the interface. It it is weaker, the rupture will be internally in mybacking paint.

Formulations can be made to achieve either :ondition. The internalstrength can be widely varied by variation binder-pigment ratio.

As stated above, the interface between the backingand the felt, the bondstrength will depend on the method of application, the thickness of thebacking, and the presence, thickness, and nature of any intermediatebacking coat.

The above described pigment coat has a soft, velvety texture, isextremely flexible, entirely free from tendency to shed pigment, and hasa remarkably clean surface that does not gather dust. It has a high bondstrength to the usual linoleum pastes.

The red slate flour has been chosen because it gives a desirable redpigmentation to the back surface of the felt. Other pigments, of course,may be substituted, depending upon the particular color desired.

The vulcanizing ingredients and their proportions are given as examplesonly. For instance, other low-temperature accelerators, 'such asTepidone, may be substituted for Butyl Zimate, and if desired,anti-oxidants may also be included,

though it has been found that the aging properties of the coating ofthis invention are fully adequate when reclaimed rubber is used evenwithout the inclusion of anti-oxidants, the coat.-' ing remainingunchanged in an oxygen bomb test corresponding to a 15 year'aging.

Instead of casein, similarly successful results have been secured withthe use of other high molecular weight water soluble organic binders, insubstantially the same proportions, including animal glue, methylcellulose, dihydroxyethyl cellulose, polyvinyl alcohol, and alginates(such as Superloid).

The purpose of these materials is to stabilize the emulsion paint, asthey all are able to function as protective colloids; to contribute tothe film strength of the backing; and to help form a non-tacky, drybacking.

The function of the rubber is to contribute to the strength of thecoating and to impart a high degree of flexibility. A proper balancebetween pigment and fillers, rubber, and water-soluble binders is theobject of this invention so as to impart the necessary flexibility withfreedom from tack and sticking, the proper degree of adhesion orinternal strength to the coating. All prior coatings to my knowledgehave failed in practice due to failure to fulfill these conditions, allof which are vital to a successful product.

Where certain types of reclaims are used, such as black tube or wholetire reclaim, there is less troublesome residual tack These otherreclaims cannot very well be used where light color is desired, thoughin other respects the results of this invention are procurable.

A natural rubber dispersion may be used in accordance with the followingformula:

' Parts by weight Hevea latex (50% solids) 32 Sulphur (50 Butyl zimate(40%)-;

Phenyl B naphthylamine 5 Zinc oxide 7 Gray slate Water-to suit Casein(10% solution) Backing paints using synthetic rubbers have also beenmade which have satisfactory removability.

if it is desired to rupture at- Examples of such formulae include:

Butyl rubber reclaim dispersion solids) Sulfur dispersion (50%) .8Accelerator .25 Zinc oxide .6 Red slate 100 Casein solution (10%)Copolymers of isobutylene and small amounts of dioleiin.

In accordance with the invention, as actual practise shows, it is vitalthat the rubber content of the backing composition not exceed 20%thereof, and preferably not exceed 18 the best results being had in thelower ranges of the order of 645%, depending on the particularrubberemployed (all being based on the dry weight of the compositions)In the case of all the above vulcanized rubber back coats, with orwithout an interposed smoothing coat of the type above, described, whenthe floor covering is removed from a sub-surface after cementing with ausual floor covering cement, the saturatedv felt strips from thesub-surface along a plane of cleavage lying intermediate the backsurface of the, saturated base (or of the interposed smoothing coat) andthe back surface of the vulcanized rubber backing coat. In the usualcase, where the smoothing coat is not used and the vulcanized rubbercoat is spread directly on the saturated felt, the plane of cleavagelies substantially at the level of the interface between the vulcanizedrubber coat and the saturated felt. However, the internal cohesivestrength of the rubber coat may be so decreased and/or its bond to thesaturated felt simultaneously so increased, as by increasing the amountof pigment in proportion to the other ingredients, that the plane ofcleavage is below the interface and involves internal rupture of thevulcanized rubber coat. Such lower plane of rupture is often more commonwhen the smoothing coat is interposed, due to the greater bond of thevulcanized rubber coat to the paint coat than to the saturated felt. As

will be understood, where it is contemplated that mented to anunderlying supporting surface by linoleum paste, comprising a fibrousbase saturated with bituminous material, an ornamental tread layer onone side of said fibrous base, and a flexible, dry, coherent non-tackybacking coat on the opposite side of said base consisting essentially ofa composition including rubber selected from the class consisting ofisobutylene-diolefin copolymer, neoprene, butadiene-styrene copolymer,vulcanized natural rubber, and vulcanized reclaim rubber, saidcomposition including pigment and a watersoluble organic binder, therubber content of said composition not exceeding 20% (by weight)thereof, the internal cohesive strength of said backing coating and itsbonding strength to the fioor covering being suificient to firmly anchorthe floor covering to an underlying layer of hardened linoleum paste ona supporting surface but at least one of said strengths beingsubstantially less than the internal cohesive strength of said saturatedbase, whereby said base is strippable as a unit from said supportingsurface after attachment thereto by such hardened paste.

2. A hard-surfaced flexible removable cover ing for floors, walls, andthe like, adapted to be cemented to an underlying supporting surface bylinoleum paste, comprising a fibrous base saturated with bituminousmaterial, a heat-cured ornamental tread layer on one side of saidfibrous base and a flexible, dry, coherent non-tacky backing coat on theopposite side of said base consisting essentially of a compositionincluding vulcanized rubber and'including pigment and a water-solubleorganic binder, the rubber content of said composition not exceeding 20%(by weight) thereof, the internal cohesive strength of said backingcoating and its bonding strength to the floor covering being suflicientto firmly anchor the floor covering to an underlying layer of hardenedlinoleum paste on a supporting surface but at least one of saidstrengths being substantially less than the internal cohesive strengthof said saturated base, whereby said base is strippable as a unit fromsaid supporting surface after attachment thereto by such hardened paste.

SAMUEL G. 'IREPP.

REFERENCES CITED The following references are of record in the file ofthis patent:

UNITED STATES PATENTS Number Name Date 1,705,273 Teague Mar. 12, 19291,911,631 Levin May 30, 1933 1,982,018 Owen Nov. 27, 1934 2,153,723 PohlApr. 11, 1939 2,327,573 Walsh Aug. 24, 1943 2,341,078 Bradley Feb. 8,1944 2,354,609 Phipps July 25, 1944

